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Thread: N to P ratio (Redfield Ratio)

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    N to P ratio (Redfield Ratio)

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    Found this interesting site:

    http://www.xs4all.nl/~buddendo/aquar...dfield_eng.htm

    The author proposes keeping N to P at a certain ratio to prevent algae - recommend an optimal point a N:P = 16 with a lower bound of 10 and upper bound of 22.
    At N:P =16, NO3:PO4=23)

    Compare to E.I. reference, the N:P is about 2.2:1 (NO3:PO4 = 3.25). So I am not sure how this 16:1 ratio really mean much if most of us following EI already put algae under control.

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    Old stuff...went over it already.

    Regards
    Peter Gwee
    Plant Physiology by Taiz and Zeiger

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    Okie

    Found the archives.
    This one out the window then.

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    Hi AQ, my ratio of nitrate,NO3(seachem flourish nitrogen) : phosphate,PO4(seachem flourish phosphorus) is 1.55ppm : 0.11ppm .

    1)Is it considered a ratio of 14:1 ?

    2)If yes, is there a need for me to up my NO3 to make it 16:1 ratio ?

    3)What is the most ideal ratio of N:P:K and Fe in terms of ppm.

    Best regards,
    zhan

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    The redfield ratio is based on marine systems and not applicable to planted tanks. It really doesn't matter what ratio of the N, P, K or Fe or other trace elements as long as they are non-limiting. The N:P ratio can be 5:1 or 15:3 and it'll still work fine.

    Regards
    Peter Gwee
    Plant Physiology by Taiz and Zeiger

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    I see...thanks for clarifying, Peter... I guess it's time for me to move on~

    cheers,
    zhan

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    Quote Originally Posted by PeterGwee
    The N:P ratio can be 5:1 or 15:3 and it'll still work fine.
    I thought this was funny... Ain't they the same?
    ~ Vincent ~ Fishes calm your mind...
    http://www.flickr.com/photos/valice/





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    Quote Originally Posted by valice
    I thought this was funny... Ain't they the same?
    Okay, forgot the ppm behind the numbers.

    Regards
    Peter Gwee
    Plant Physiology by Taiz and Zeiger

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    Actually the more I dig in to this the more amazing I find - not to doubt the non-limiting approach. Rather it is that there are more to it in the truth out there, but for the beginners like us are best leaving it to the expert and just adapt the non-limiting regime.
    "Ferts are cheap unless you are growing large acre of crops." So just go non-limiting and save the trouble.
    But there is exception to every rule : ) if you want to bring out the red of certain red plant - which N:P ratio will deserve some attention.

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    Quote Originally Posted by dc88
    Actually the more I dig in to this the more amazing I find - not to doubt the non-limiting approach. Rather it is that there are more to it in the truth out there, but for the beginners like us are best leaving it to the expert and just adapt the non-limiting regime.
    "Ferts are cheap unless you are growing large acre of crops." So just go non-limiting and save the trouble.
    But there is exception to every rule : ) if you want to bring out the red of certain red plant - which N:P ratio will deserve some attention.
    Try looking into plant physiology then. What does the leave of a plant consist of? Look more into it and why is there red colouration and etc. A very red plant is a stressed/unhealthy plant.

    Regards
    Peter Gwee
    Plant Physiology by Taiz and Zeiger

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    You can also do like many good photogrpahers do, use phot shop and adjust the hue and suddenly you have blood red plants(try it sometime, you'll be amazed what a little PS ing will do).

    You can see how it influences your colorations in your tanks, and suddenly those subtle but rather intense colors pop right up and you can look at the other colors and see they did a little something.

    Photo's and your eyes are two very different things.
    the best Red macrandra I've ever seen was grown at 2w/gal no FL's, peat, soft water etc, and rather high NO3's, but you can stress the plants and bring it out a trad more, but it's much easier to do and keep that up at lower light level also.


    Regards,
    Tom Barr

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